// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// This file is based on http://osxbook.com/book/bonus/chapter10/light/

#include "content/browser/device_sensors/ambient_light_mac.h"

#include <utility>

#include "base/mac/scoped_cftyperef.h"
#include "base/mac/scoped_ioobject.h"

namespace content {

namespace {
    enum LmuFunctionIndex {
        kGetSensorReadingID = 0, // getSensorReading(int *, int *)
        kGetLEDBrightnessID = 1, // getLEDBrightness(int, int *)
        kSetLEDBrightnessID = 2, // setLEDBrightness(int, int, int *)
        kSetLEDFadeID = 3, // setLEDFade(int, int, int, int *)
    };
} // namespace

// static
std::unique_ptr<AmbientLightSensor> AmbientLightSensor::Create()
{
    std::unique_ptr<AmbientLightSensor> light_sensor(new AmbientLightSensor);
    return light_sensor->Init() ? std::move(light_sensor) : nullptr;
}

AmbientLightSensor::~AmbientLightSensor()
{
    if (!io_connection_)
        IOServiceClose(io_connection_);
}

AmbientLightSensor::AmbientLightSensor()
    : io_connection_(IO_OBJECT_NULL)
{
}

bool AmbientLightSensor::Init()
{
    // Tested and verified by riju that the following call works on
    // MacBookPro9,1 : Macbook Pro 15" (Mid 2012 model)
    // MacBookPro10,1 : Macbook Pro 15" (Retina Display, Early 2013 model).
    // MacBookPro10,2 : Macbook Pro 13" (Retina Display, Early 2013 model).
    // MacBookAir5,2 : Macbook Air 13" (Mid 2012 model) (by François Beaufort).
    // MacBookAir6,2 : Macbook Air 13" (Mid 2013 model).
    // Testing plans : please download the code and follow the comments :-
    // https://gist.github.com/riju/74af8c81a665e412d122/
    // and add an entry here about the model and the status returned by the code.

    // Look up a registered IOService object whose class is AppleLMUController.
    base::mac::ScopedIOObject<io_service_t> service_object(
        IOServiceGetMatchingService(kIOMasterPortDefault,
            IOServiceMatching("AppleLMUController")));

    // Return early if the ambient light sensor is not present.
    if (!service_object)
        return false;

    // Create a connection to the IOService object.
    kern_return_t kr = IOServiceOpen(service_object, mach_task_self(), 0, &io_connection_);

    // IOServiceOpen error.
    if (kr != KERN_SUCCESS || io_connection_ == IO_OBJECT_NULL)
        return false;

    uint64_t lux_values[2];
    return ReadSensorValue(lux_values);
}

bool AmbientLightSensor::ReadSensorValue(uint64_t lux_values[2])
{
    uint32_t scalar_output_count = 2;
    kern_return_t kr = IOConnectCallMethod(
        io_connection_, LmuFunctionIndex::kGetSensorReadingID, nullptr, 0,
        nullptr, 0, lux_values, &scalar_output_count, nullptr, 0);

    return kr == KERN_SUCCESS;
}

} // namespace content
